They are commonly called silk trees or sirises. Peculiarly, the obsolete form of spelling the scientific name - with double 'z' - has stuck, so that another commonly used term is albizzias (though the form albizias is also found, particularly in species that are not widely known under a common name). The scientific name refers to the Italian nobleman Filippo degli Albizzi, who in the mid-18th century introduced siris to Europe.

These are usually small trees or shrubs with a short lifespan - though the famous Samán del Guère near Maracay in Venezuela is a huge Albizia saman specimen and several hundred years old. The leaves are pinnately or bipinnately compound. Their small flowers are in bundles, with showy stamens much longer than the petals. Confusingly, some species are given the name "mimosa" which correctly belongs to species in the related genus Mimosa. Unlike those of Mimosa, Albizia flowers have much more than 10 stamens. Albizia can also be told apart from another large related genus, Acacia, since its flowers have their stamens joined at the base whereas in Acacia stamens are free (separated).